In one conventional attempt to obtain white light, a phosphor sheet, in which a powdery red phosphor that emits red fluorescence when irradiated with blue light and a green phosphor that emits green fluorescence when irradiated with blue light are dispersed in a resin material having high visible light transmittance, is irradiated with light emitted from a blue light-emitting diode (blue LED) so that red light and green light are caused to be emitted from the phosphor sheet irradiated with the blue light, and then the blue light is mixed with red light and green light to produce white light (Patent Literature 1).